• Fractions
• Common denomination: more adding and subtracting
• Mastery PD Materials

## Common denomination: more adding and subtracting

Spine 3: Fractions – Topic 3.8

### Introduction

Learn to add and subtract fractions with different denominators by first finding a common denominator. Compare fractions using a range of methods, including converting to a common denominator.

### Teaching points

• Teaching point 1: In order to add related fractions, first convert one fraction so that both share the same denominator (a ‘common denominator’).

• Teaching point 2: To subtract related fractions, first convert one fraction so that both share a common denominator.

• Teaching point 3: The common denominator method can be extended to adding and subtracting non unit related fractions.

• Teaching point 4: To add and subtract non-related fractions, the product of the two denominators provides a common denominator.

• Teaching point 5: Converting to common denominators is one of several methods that can be used to compare fractions.

• Primary
• KS2
• Year 5